Update supported configuration validation after feature composition refactor

[nradakovic]

What

Run and update validation for the supported Linux and QNX toolchain configurations after introducing shared and platform-specific feature composition.

The goal is to confirm that the structural refactor is behavior-preserving across supported scenarios.

Acceptance Criteria

• Supported Linux configurations continue to pass after the refactor.
• Supported QNX configurations continue to pass after the refactor.
• Validation failures caused by the new composition model are fixed or explicitly tracked.
• The post-refactor validation result is documented and usable as release evidence.

How

• Use the existing example and validation matrix as the baseline.
• Run the relevant host, cross, runtime-specific, and QNX validation scenarios after each major refactor step.
• Investigate regressions to determine whether they come from feature ownership changes, ordering changes, or platform-specific assembly issues.
• Keep validation aligned with currently supported configurations only.